Cancer research depends on the availability of effective shared resources. Because experiments conducted only in tissues culture cells cannot duplicate the information obtained by studying the pathogenesis of cancer development in vivo, an increasingly important aspect of studying cancer is the development and availability of animal models of cancer. In addition, it is becoming increasingly apparent that the ability to produce conditional genetic models in the mouse lends itself particularly well to cancer studies At Beth Israel Deconess Medical Center (BIDMC), there exists a significant number of researchers carrying out studies of cancer which are amenable to study in the mouse model, and in addition we already have an effective transgenic facility in our institution. Our overall goals are to further the development of useful transgenic mouse models of human cancer, particularly those involving conditional genetic models, but developing a shared resource which encourages and fosters the development of these models. The funding of a Shared Resource for Transgenic Mouse Models of Cancer will allow us to investigate the biology, pathogenesis, and treatment of a number of important cancers in vivo. The specific aims of the resource are to: 1) Provide advice on design of experiments, disseminate information to investigators, and encourage the development of these models; 2) To organize and run a monthly meeting of investigators working on these models; 3) To produce the transgenic models of cancer in mice for investigators at BIDMC working on cancer related projects; 4) To maintain colonies of mice useful to multiple cancer investigators, including tissue specific Cre and tet transactivator (tTa) lines, and indicator lines, and indicator lines; 5) To produce chimeric mice from -/- ES cells, which will be useful in studying gens in which homozygous mutation produces mortality; 6) perform injection of +/- ES cells for production of floxed knockout alleles and knock-ins; 7) Perform rederivation of lines from other institutions (which are often infected with various pathogens; 8) Perform embryo freezing of valuable transgenics for long term preservation; and 9) To distribute animals and embryos to other investigators. This shared resource, in addition to servicing BIDMC cancer researchers will serve as a major stimulus for development of novel animal models of cancer.